Bedside diagnosis for neurological residents in neurological emergencies: a retrospective analysis

BACKGROUND

Critical assessment of diagnostic accuracy is indispensable to resident training and medical education, especially in regard to our situation of the extremely low rate of autopsy. Recent setup of advanced technology for neurological diagnosis has resulted in a tendency to overuse these tools at the expense of using classic bedside diagnostic approach. Disclosing the common errors of daily practices among neurological residents necessitates implementing this pioneer study.

METHODS

The tentative diagnosis of each patient, as performed by neurological residents after finishing bedside diagnostic processes, was assessed by final diagnosis concluded from clinical syndrome and/or the results of laboratory studies. The overall rate of diagnostic error and the frequency of diagnostic inaccuracy in various disease entities were evaluated. The reason for the diagnostic error was determined by reviewing the records regarding the entire diagnostic process.

RESULTS

1336 consecutive patients from January 1990 to December 1990 were recruited for this study. The initial bedside diagnosis was correct in 901 (67%) patients. No definite final diagnosis could be obtained in 169 (13%) patients. The diagnoses were incorrect in 266 (20%) patients. The highest rate of inaccuracy was found in the diagnosis of subdural hematoma (56%). The other common diseases of high rate of diagnostic inaccuracy were myasthenia gravis (50%), subarachnoid hemorrhage (42%), Guillain-Barré syndrome (40%), traumatic disorders (39%), herniation of intervertebral disc (33%), metabolic encephalopathy (30%), infection of central nervous system (30%), intracranial neoplasm (24%), drug overdose or intoxication (22%), and mixed neurological and metabolic encephalopathy (21%). The explored reasons for diagnostic inaccuracy were errors of reasoning (38%), inadequate data base (35%), and inadequate fund of knowledge (27%).

CONCLUSIONS

This study confirmed that the basic methods of bedside diagnosis with a standardized sequence of history taking, physical examination and diagnostic reasoning are currently still the most fundamental process of achieving an accurate diagnosis in neurological emergencies. No shortcut or mechanical substitute is available for clinical diagnosis.

Valproic acid suppresses the synaptic response mediated by the NMDA receptors in rat amygdalar slices

The mechanism of action of the anticonvulsant drug valproic acid (VPA) was studied in rat amygdaloid slices using intracellular recording techniques. In the presence of bicuculline (20 microM), stimulation of the endopyriform nucleus evoked an excitatory postsynaptic potential (EPSP) followed by a paroxysmal depolarizing shift (PDS). Superfusion of VPA (2 mM) reversibly suppressed the PDS. Synaptic response mediated by the N-methyl-D-aspartate (NMDA) receptors (EPSPNMDA) was isolated pharmacologically by application of a solution containing nonNMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and gamma-aminobutyric acid receptor antagonist bicuculline (20 microM). VPA (0.2-10 mM) reversibly reduced the amplitude of the EPSPNMDA in a dose-dependent manner. Higher concentration of VPA (10 mM), in addition, suppressed the normal synaptic transmission. These results suggest that VPA's anticonvulsant effect is due, at least in part, to its blocking action on the EPSPNMDA.

Prevalence of familial systemic lupus erythematosus in Taiwan

A survey of familial occurrence of systemic lupus erythematosus (SLE) was conducted among 728 first-degree relatives of 102 SLE patients. All of the patients were from the rheumatology ward or outpatient clinic of Kaohsiung Medical College. Ten familial members (9.80%) in the 102 patients with SLE suffered from the same disease. Among them, one (20%) was from the 5 male patient families and 9 (9.28%) were from the 97 female patient families. The overall prevalence of SLE in first-degree relatives of SLE patients was 1.37% (10/728).

The modulatory effect of immunoglobulin G on the CD23 and HLA-DR expression and cytokine production in different groups of asthmatic patients

The therapeutic effect and mechanism of action of immunoglobulin G (IgG) on bronchial asthma are not defined. Recently, it has been proposed that mononuclear cell (MNC) infiltration in the airway plays a role in the pathogenesis of asthma. In this study, we evaluated the effect of IgG on the cell receptor expression and cytokine production of MNC from two groups (young atopic and old non-atopic) of stable asthmatic patients. MNCs from both asthmatic patients and normal healthy individuals were obtained after Ficoll-Hypaque separation. Cells were cultured in serum free AIM-V medium, with or without phytohemagglutinin (PHA, 5 micrograms/ml) and IgG (100 micrograms/ml). After culture, MNCs were harvested and stained with monoclonal antibodies for HLA-DR (Ia), CD23 and CD3. MNC supernatants were collected for IL-2 and IL-4 measurement. The results showed an enhancing effect of IgG on young atopic MNC proliferation when stimulated with PHA. The production of IL-2 and IL-4 from MNCs were significantly higher in old non-atopic asthmatics after PHA stimulation. The CD23, but not HLA-DR, expression on CD3 positive T cells and cytokines (IL-2 and IL-4) production were increased by IgG when stimulated with PHA in young atopic asthmatics. To the contrary, the effect of IgG on PHA stimulated MNC proliferation, CD23 and HLA-DR expression on CD23 positive T cells in old non-atopic asthmatics were trivial. Only IL-4 production can be significantly inhibited by IgG. These results suggested that the therapeutic effect of IgG on asthmatics might be variable in different groups of asthmatics.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma arginase concentration measured by an enzyme-linked immunosorbent assay (ELISA) in normal adult population

Human liver arginase has many biological effects on lymphocytes, macrophages, liver cells, and tumor cells, in addition to its major role in the liver urea cycle. We have developed a sandwich enzyme-linked immunosorbent assay (ELISA) method to quantitate arginase concentrations in plasma that can be applied to various body fluids. The sensitivity was 2.5 ng/mL. The coefficients of variation were good both in intra- and inter-assay. Using this method to study the stability of an arginase preparation, we found that plasma arginase was stable for only 1 or 2 days even at temperatures as low as 4 degrees C. The mean plasma level was 41.0 +/- 3.3 ng/mL (mean +/- SE) in 143 normal subjects. There was no age difference in the general population and in the male group. However, in the female group, the plasma arginase level increased with age (p = 0.05). Its biological significance was unclear. As a whole, the ELISA method for the measurement of arginase concentration in the body fluid is convenient and reliable.

Behçet's disease with inferior vena cava occlusion--a case report

Behçet's disease is a chronic relapsing inflammatory process affecting mucocutaneous, ocular, intestinal, articular, vascular, urogenital, and neurologic systems. Vascular lesions include superficial thrombophlebitis, large vein thrombosis and arterial aneurysm. The underlying pathologic feature was thought to be vasculitis. We report a case of a 37-year-old male patient suffering from frequent attacks of leg swelling and tenderness. Progressive engorgement of abdominal superficial veins was observed. Venography demonstrated evidence of deep vein thrombosis in both limbs. MRI of the abdomen showed thrombosis of the inferior vena cava with collateral circulation. The above symptoms improved after treatment.

Enhancement of NMDA receptor-mediated synaptic potential by isoproterenol is blocked by Rp-adenosine 3',5'-cyclic monophosphothioate

The intracellular mechanisms underlying the facilitatory action of isoproterenol (Iso) on the NMDA receptor-mediated synaptic potential (EPSPNMDA) was investigated in an in vitro slice preparation of rat amygdala. Intracellular recordings were made from basolateral amygdala neurons in the presence of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM) and picrotoxin (50 microM) which block non-NMDA and GABAA receptors, respectively. Superfusion of Iso (15 microM) produced a sustained increase in EPSPNMDA. Rp-adenosine-3',5'-cyclic monophosphotioate (Rp-cAMPS), a potent inhibitor of protein kinase A (PKA) alone decreased the amplitude of EPSPNMDA below baseline values and prevented the subsequent potentiation by Iso. Forskolin, a direct activator of adenylate cyclase, mimics the effect of Iso, and Rp-cAMPS also reversed forskolin-induced enhancement of EPSNMDA. These results suggest that cAMP-dependent protein kinase mediates the enhancement of EPSPNMDA by Iso in the amygdala.

Use of monoclonal antibodies to isolate and characterize Cyn d I, the major allergen of Bermuda grass pollen

BACKGROUND

Cyn d I has been found to be the major allergen of Bermuda grass (Cynodon dactylon) pollen, but its exact nature remains to be clarified.

METHODS

Cyn d I, the major allergen of Bermuda grass (Cynodon dactylon) pollen, was purified by monoclonal antibody (MoAb) affinity chromatography, and its biochemical and immunologic properties were characterized. Anti-Cyn d I MoAb 4-37, which recognizes all of the isoallergens of Cyn d I, was chosen as the immunosorbent.

RESULTS

The purified protein has an amino acid composition similar to that of the group I allergens of other grass pollens. It appears as a single 34 kd band or as a mixture of 34 and 29 kd polypeptides in sodium dodecylsulfate-polyacrylamide gel electrophoresis analysis. The hydrophobicity of these two polypeptides is similar because they have the same retention time on a C18 reverse-phase column when a trifluoroacetic acid/H2O/CH3CN buffer system is used. The N-terminal amino acid sequence of the 34 kd component has a 60% homology with residues of 1-25 of Lol p I, whereas that of the 29 kd component has a 68% homology with residues 31-68 of Lol p I. In addition, this 29 kd polypeptide can be recognized by another anti-Cyn d I MoAb 1-61.

CONCLUSIONS

These results suggest that the 29 kd component is derived from Cyn d I. In spite of the similarity in the amino acid composition between Cyn d I and group I allergens of other grass pollens, none of our four anti-Cyn d I MoAbs cross-reacted with 10 other grass pollens tested, including ryegrass pollen. Despite biochemical similarity with other group I allergens, the B-cell epitopes on Cyn d I are different from those on other grass pollens.

[Pulmonary cryptococcosis: analyses of 17 cases in VGH-Taipei]

Seventeen patients with pulmonary cryptococcosis collected at VGH-Taipei from 1967 to 1991 were analysed. Their ages ranged from 16 to 70 years with a mean of 45.2. Twelve were men and five were female. The chief characteristic symptoms and signs were cough (58.8%), fever (29.4%) and dyspnea (23.5%). Nearly one third of cases were asymptomatic and presented with abnormal chest roentgenogram. The chest roentgenogram included single nodule or mass (41.2%), multiple nodules (35.3%), pneumonic patch or consolidation (23.5%). In addition, 5 cases (29.4%) and 4 cases (23.5%) were combined with cavitary formation and pleural effusion respectively. Only two cases had associated immunologic deficiency. No patient was found to have history of breeding pigeon. Five cases didn't receive any treatment but were followed from 6 months to 5 years. The remaining 12 cases underwent medical treatment, surgical resection or a combination of both. Prognosis was good in all except one patient who died of multiple myeloma.

Enhanced eosinophil luminol-dependent chemiluminescence and complement receptor expression by platelet-activating factor and interleukin-5

The cytokine interleukin-5 (IL-5) and the lipid mediator platelet-activating factor (PAF) have both been shown to be involved in eosinophil differentiation and activation. We have measured and compared the effect of PAF and IL-5 on human eosinophils in terms of their luminol-dependent chemiluminescence (CL) response and their expression of complement receptors, CR1 and CR3. Both IL-5 and PAF enhanced the eosinophil CL response. The optimal concentrations were 40 U/ml for IL-5, and 10(-6) M for PAF. The priming effect of IL-5 was slow and reached a maximal response after 90 minutes incubation. In contrast, the effect of PAF peaked early and declined during incubation. In the complement receptor study, only PAF was able to enhance CR3 expression (p < 0.05) while the effect of IL-5 on eosinophil complement receptor expression was negligible. These results provide evidence that both inflammatory mediator (PAF) and cytokine (IL-5) can activate eosinophils but the effects of IL-5 and PAF on eosinophil CL response appear to be distinct. The activation of eosinophils by PAF and IL-5 may occur through different mechanisms.

[Clinical experience with fluconazole monotherapy in cryptococcal meningitis: report of four cases]

Four patients with cryptococcal meningitis have been treated with fluconazole in the past two years at the Department of Neurology, National Cheng Kung University Medical Center. There were three women and one man. Two patients had a history of anemia and one had undergone a splenectomy due to hypersplenism. Two patients were healthy before the onset of meningitis. After receiving fluconazole 300 mg per day for 8 to 13 weeks, three patients were cured without clinical evidence of recurrence during follow-up lasting from 2 to 17 months. One patient died from pneumothorax as a complication of subclavian vein cannulation. During the treatment course, there was no side effect except for one patient who had transient elevation of the GOT and GPT values which reversed spontaneously without a change in dosage. In the three successfully treated cases, the cryptococcal antigen titers began to decrease after the first week of treatment. Our preliminary experience shows that fluconazole alone is an effective and safe drug for the treatment of cryptococcal meningitis.

The effects of Chinese herbs on improving survival and inhibiting anti-ds DNA antibody production in lupus mice

Systemic lupus erythematosus (SLE) is an important autoimmune disease with multiple organ system involvement. From preliminary studies, we have found that six Chinese herbs: Atractylodes ovata, Anqelica sinensis, Cordyceps sinensis, Liqustrum lucidum, Codonopsis pilosula and Homo sapiens can improve defective in vitro interleukin-2 (IL-2) production in patients with SLE. In order to investigate the in vivo effects of these herbs, we used NZB/NZW F1 mice, a typical lupus animal model used to test these herbs. It was found that C. pilosula, H. sapiens and C. sinensis could prolong the life span of female NZB/NZW F1 mice and inhibited anti-ds DNA production. Although A. sinensis could prolong the life span of experimental mice, it did not inhibit the production of anti-ds DNA antibody. These herbs may have great potential for the management of human SLE in the future.

Methotrexate pneumonitis in bronchial asthma

Methotrexate pneumonitis is one of the most unpredictable and potentially serious adverse effects associated with the use of low-dose pulse methotrexate in treating rheumatoid arthritis. However, its occurrence in treating bronchial asthma has never been reported. A patient with steroid-dependent bronchial asthma developed interstitial pneumonitis during methotrexate therapy. Dyspnea, fever and oral ulcer occurred successively during the initial 4 months of intermittent low-dose methotrexate pulse therapy. Despite severe hypoxemia and interstitial infiltration in both lung fields, the lung lesions disappeared after treatment with corticosteroid and discontinuation of methotrexate therapy. In conclusion, methotrexate pneumonitis might develop after treatment. Once pneumonitis is suspected, methotrexate should be withdrawn.

Hydrochlorothiazide-induced pulmonary edema: a case report and literature review

A 67-year-old man developed non-cardiogenic pulmonary edema after taking a hydrochlorothiazide (HCTZ) tablet. The symptoms remitted following supportive treatment but recurred after rechallenge. Immunologic studies showed increased immunoglobulin E, negative lymphocyte transformation test when exposed to HCTZ, normal blood lymphocyte subpopulations and complement levels, and negative antinuclear antibodies. We reviewed 22 previous reported cases and emphasized that physicians should be aware of this rare but life-threatening reaction.

[Long term and low dose treatment with methotrexate in corticosteroid-dependent asthma--two-year clinical experience]

Ten patients with corticosteroid-dependent asthma were treated with long-term and low dose methotrexate (MTX) for its corticosteroid-sparing effect. The average age was 51.2 years (ranged 24 to 67). Three were women. Despite the use of maximal doses of bronchodilators, their daily prednisolone dosages were always more than 10 mg during an average period of 2.75 years (ranged 1 to 6 years). Following the use of oral MTX, 15mg weekly from more than 6 months (averaged 11.8 months; ranged 6 to 15 months), the average daily requirement of prednisolone decreased from 14.5 to 6.5 mg (p < 0.01). Among them, four did not need steroid and the other six had a marked subjective improvement in breathing, cough and nocturnal dyspnea. However, three of them could not have steroid dose reduced. As for adverse reactions to MTX in ten patients, two patients had nausea and vomiting, two had skin eruption, three had somnolence, and one had elevated sGOT (78 U/L). The adverse effects were all transient. Neither oral ulcer, nor leukopenia was found among them. This study suggests long-term low dose oral MTX may have a steroid-sparing effect in steroid-dependent asthmatic patients. Their adverse effects were mild and transient.

Sustained enhancement of NMDA receptor-mediated synaptic potential by isoproterenol in rat amygdalar slices

The effect of isoproterenol (Iso) on synaptic transmission mediated by the N-methyl-D-aspartate (NMDA) receptors (EPSPNMDA) was investigated in slices of rat amygdala using intracellular recording techniques. EPSPNMDA was isolated pharmacologically by application of a solution containing the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM) and GABAA receptor blocker bicuculline (20 microM). Superfusion of Iso (15 microM) produced a long-lasting enhancement of EPSPNMDA. Pretreatment the slices with propranolol (10 microM) completely prevented the effect of Iso confirming the mediation by beta-adrenergic receptors. These results provide the direct evidence for adrenergic modulation of excitatory amino acid neurotransmission in the vertebrate central nervous system.

Alteration of intracellular DNA and RNA patterns by liver arginase studied with flow cytometry

Previous study of lymphocyte proliferation in the presence of liver arginase has indicated that arginine-depletion in the culture medium plays an important role in inhibiting cell proliferation. The inhibitory effect of both liver arginase and arginine-free condition on DNA, RNA and protein syntheses in PHA-stimulated lymphocytes were studied in cultures by measuring the incorporation of labeled precursors. Simultaneously, their influence on DNA and RNA contents in cells stained by acridine orange was investigated by automated flow cytometry. With 3 micrograms/ml arginase, the syntheses of DNA, RNA and protein were markedly inhibited after 72 h of culture. The degrees of inhibition were close to that induced in an arginine-free condition. The DNA and RNA contents of the individual cell, either cultured with 3 micrograms/ml arginase or in arginine-free medium, were arrested in G0/G1 phase. The results of cell arrest in G0/G1 phase were similar whether the cells were cultured for 24, 48 or 72 h.

The identification of an eosinophil differentiation factor in culture supernatant of mononuclear cells from asthmatics

Although peripheral eosinophilia is a common feature of bronchial asthma, the precise mechanism of its production is still unknown. It has recently been reported that murine interleukin-5 (IL-5) can cross-react with human cells and selectively stimulates the proliferation and differentiation of eosinophils. This study identified the IL-5-like activity in culture supernatants of peripheral blood mononuclear cells (MNCs) from asthmatic patients. Murine recombinant IL-5 (rIL-5) was used as a positive control; the number of eosinophils was determined by both Wright's stain and eosinophil peroxidase measurement. Time course and dose response studies showed that rIL-5 at 40 U/ml induced a maximal eosinophil differentiation after a three week incubation with cord blood MNCs. Unstimulated MNC supernatants obtained from asthmatics possessed a higher eosinophil differentiation activity (OD490, 0.09 +/- 0.02, n = 23) than those obtained from the normals (0.03 +/- 0.01) (P < 0.02). This activity in unstimulated MNC supernatant can be neutralized by anti-IL-5 antibodies. Neither Bermuda grass- nor phytohemagglutinin-stimulated MNC supernatant showed a statistical significance between these two groups. The IL-5-like activity was associated with a protein of MW around 30kD as determined by Superose-12 PG gel filtration. In conclusion, MNC culture supernatants derived from asthmatics contained an eosinophil differentiation activity, which might be important for regulation of eosinophil generation and thus contribute to the asthma-related eosinophilia.

Status of follow-up among patients with epilepsy in epilepsy clinic

Out of 238 consecutive patients entering our epilepsy clinic from October 1988 till March 1990, the status of follow-up was evaluated in October 1990. One hundred patients (42%) could adhere to the follow-up appointment and 33 patients (14%) visited the clinic irregularly. A total of 105 patients (44%) failed to return for the follow-up at least for 2 months dated backward from October 1990. Seventy-five percent of the patients lost the follow-up within 6 months. The main reasons of the dropout were poor seizure control, seizure free, denial of epilepsy, receiving operation in other hospitals. The appropriate strategies to aid in adherence to medical care among patients with epilepsy should be formulated through the analysis of factors contributing to the dropout, which might be strongly influenced by different medical and sociocultural backgrounds all over the world.

The effects of asthmatic mononuclear cell cultured supernatant on human eosinophils-chemiluminescence response, complement receptor expression and cellular density alteration

We investigated the contributing effect of mononuclear cell (MNC) on granulocyte function in asthmatics. MNC, obtained from either normal subjects or asthmatics, were cultured with or without phytohaemagglutinin. The supernatants were tested on granulocyte luminol-dependent chemiluminescence (CL) response. The optimal incubation time was 30 min for neutrophils and 90 min for eosinophils. There was a dose-dependent enhancement of CL response by MNC supernatant on both neutrophils and eosinophils. When comparing the activities of MNC supernatants between asthmatics and normal, there was a significant enhancement of eosinophil CL response by MNC supernatants of asthmatics (70 +/- 24% from 29 +/- 28%, P = 0.0043). However, the degree of enhancement in neutrophil CL response was similar between the MNC supernatants of asthmatics and normal subjects. MNC supernatant not only enhanced eosinophil CL response, but also induced eosinophil hypodensity change (12 +/- 4% in RPMI, 26 +/- 10% in MNC supernatant), and enhanced complement receptor CR3 expression (102.4 +/- 25.5 in PRMI, 111.7 +/- 17.7 in MNC supernatant). These results provide evidence that MNC activation might contribute to the eosinophil activation in asthmatics.

Comparison on bioequivalence of four phenytoin preparations in patients with multiple-dose treatment

In previous pharmacokinetic studies on phenytoin, the authors found that a hybrid parameter, Vd/F, was much higher in Chinese subjects. It could be due to a lower bioavailability (F) of the tested phenytoin preparations and/or a higher volume of distribution (Vd) in Chinese. Therefore, the relative bioavailability of four phenytoin oral preparations, i.e. Dilantin (Taiwan), Dilantin (USA), Aleviatin (Taiwan), and Aleviatin (Japan), were compared in patients who regularly took Dilantin (Taiwan) with their phenytoin plasma level at steady state. Twenty-four-hour area under curve was measured by an HPLC method after substituting the daily dose with each 300-mg dose of the test preparation. The plasma level resulted from Dilantin (USA) was found significantly higher than that from Dilantin (Taiwan). Similarly, Aleviatin (Japan) gave a significantly higher plasma level than Aleviatin (Taiwan). The study in part explained the unexpected high Vd/F of phenytoin in previous studies.

Glucocorticoid resistance in chronic asthma. Peripheral blood T lymphocyte activation and comparison of the T lymphocyte inhibitory effects of glucocorticoids and cyclosporin A

A total of 37 chronic severe asthmatic patients with documented reversible airways obstruction were classified as glucocorticoid sensitive or resistant according to changes in the FEV1 following a course of oral prednisolone. The phenotype and expression of activation molecules on peripheral blood T lymphocytes from these patients just before the course of prednisolone were studied using flow cytometry. The resistant patients had significantly elevated percentages of T lymphocytes expressing the activation molecules IL-2R and HLA-DR compared to the sensitive patients. There were no differences between the patient groups in the percentages of peripheral blood T lymphocytes expressing the phenotypic markers CD4 and CD8. Peripheral blood mononuclear cells (PBMC) from 29 patients were cultured in vitro with the T lymphocyte mitogen PHA in the presence or absence of dexamethasone or cyclosporin A. Dexamethasone (10(-7) mol/L) significantly inhibited the proliferation of T lymphocytes from the sensitive but not the resistant asthmatic subjects. In contrast, cyclosporin A (500 ng/ml) inhibited proliferation of T lymphocytes from both the sensitive and the resistant asthmatic subjects, although the effect was less marked in the latter group. Inhibition of elaboration of interleukin-2 and interferon-gamma by mitogen-stimulated T lymphocytes from sensitive and resistant asthmatic patients was also studied. Dexamethasone (10(-7) mol/L) significantly inhibited the production of interleukin-2 and interferon-gamma by proliferating T lymphocytes isolated from the glucocorticoid-sensitive but not the resistant chronic asthmatic patients. Cyclosporin A (500 ng/ml) inhibited the elaboration of both lymphokines by T lymphocytes derived from both patient groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucocorticoid resistance in chronic asthma. Glucocorticoid pharmacokinetics, glucocorticoid receptor characteristics, and inhibition of peripheral blood T cell proliferation by glucocorticoids in vitro

A total of 37 chronic, severe, nonsmoking asthmatic patients with documented reversible airways obstruction were classified as glucocorticoid-sensitive or -resistant on the basis of changes in FEV1, FVC, and peak expiratory flow (PEF) after oral prednisolone. The resistant patients showed no significant improvements in airflow limitation. Phytohemagglutinin (PHA)-induced proliferation of peripheral blood T lymphocytes from the sensitive but not the resistant asthmatic patients was significantly (p less than 0.01) inhibited by dexamethasone (10(-7) mol/L), reflecting a shift of the dose-response curve. When all the asthmatic patients were analyzed together, there was a significant correlation between the degree of sensitivity of T cells to dexamethasone and the clinical responsiveness to prednisolone (p less than 0.01). No differences were observed between six of the sensitive and resistant patients in the clearance of plasma prednisolone derived from orally administered prednisone. Peripheral blood mononuclear cell glucocorticoid receptors were also characterized in five sensitive and seven resistant patients. The numbers and binding affinities of these receptors could not account for the observed difference in the susceptibility of these cells to functional inhibition by dexamethasone in vitro. These results suggest that clinical glucocorticoid resistance in chronic asthma does not reflect abnormal glucocorticoid clearance but may be due at least partly to a relative insensitivity of T lymphocytes to glucocorticoids. This lack of sensitivity is unexplained but is not attributable to abnormalities of cellular glucocorticoid receptors.

The identification of PAF-release-enhancing activity in culture supernatant of mononuclear cells from asthmatics. Correlation between lymphocyte responses and immediate type hypersensitivity

Cytokines from asthmatic mononuclear cells (MNC) cultured with Bermuda Grass pollen extract (BG), were tested for their effect on leukotriene B4 (LTB4) and platelet-activating factor (PAF) generation by neutrophil under calcium ionophore stimulation. Three groups were enrolled in this study: 9 allergic asthmatics showing skin intradermal test positive to BG, 12 non-allergic asthmatics and 5 normal individuals. Results showed that the stimulation index of BG on MNC and the mediator-release enhancing activity from both allergic and non-allergic asthmatics were similar; neither showed significant increase when compared to that of normal individuals. However, there was a significant increase in PAF-release-enhancing activity in unstimulated MNC supernatant from both allergic and non-allergic asthmatics (618 +/- 75 pg/10(6) neutrophils and 569 +/- 60 pg/10(6) neutrophils) when compared to that of normal individuals (460 +/- 40 pg/10(6) neutrophils). This PAF-release-enhancing activity did not correlate with either skin test reactivity or the amount of BG specific IgE antibodies. The PAF-release-enhancing activity in unstimulated MNC supernatants from asthmatics suggesting that there is a pre-activation of MNC which might contribute to the asthmatic reaction through generation of PAF by neutrophils.